This invention relates to a connecting means for use in an electrical connector for making electrical contact to multi-conductor flexible flat cable.
The above-mentioned flexible flat cable is a relatively recent development, and is utilized in making electrical connections in electronic circuits. In such use, said cable is required to be provided, at the extremities thereof, with a terminal member maintained in permanent electrical contact with the conductors contained in the cable.
The contactor known in the prior art and used for the above-mentioned purpose is punch formed from a relatively thin metal plate of a suitable hardness and tenacity such as beryllium copper or phosphor bronze and provided with a U-shaped pair of sharply pointed tines, which pierce the insulator of said flexible flat cable to expose the conductor therein and firmly hold the thus exposed conductor by the side walls of a U-shaped crotch to form a permanent electrical contact.
Such a connecting method, however, has a serious drawback. Although the above-mentioned method does not result in a particular problem in the case where each conductor in said flexible flat cable is composed of a single wire, the conductor, if composed of a stranded structure of a plurality of thin wires, is apt to be deformed when pressed into the U-shaped crotch of the tines, to a shape easily accomodatable in said crotch. Such deformed stranded structure results in a lowered holding pressure of the contactor against the conductor after insertion thereof and eventually leads to losing electrical contact after prolonged use.
In order to avoid this difficulty to the contacting force may be increased by pressing the conductor in the cable down to the bottom of the U-shaped crotch and thus concentrating the wires of deformed stranded structure forcedly into a determined position. However, in order that the inserted conductor can be accomodated in the bottom of the U-shaped crotch, this bottom portion must be provided with suitable elasticity. Otherwise, the forced insertion of the conductor into said bottom will either result in the breakage of the stranded thin wires of the conductor or result in a permanent distortion of the U-shaped contactor, thus seriously affecting the electrical connecting properties.